In general, a power transistor, and more particularly, a higher frequency power transistor may be designed for lower on-resistance, capacitance, and/or inductance. Transistors may be designed to operate over a wide variety of conditions depending on the application. In many applications, the transistor may be the limiting factor on the performance that can be obtained in a system. Also, the transistor may contribute significantly to the overall power dissipation and/or efficiency of the system.
Increasing transistor power density may be one path to increasing device performance. Increasing the power density of a transistor reduces the size involved to deliver a predetermined power level. Typically, reducing the physical dimensions of the transistor may result in a corresponding reduction in device parasitics. Higher switching frequencies, higher operating frequency, and/or wider bandwidth are examples of enhanced performance of the transistor. On-resistance per unit area also may decrease due to the increased packing density of transistors. Another result may be that the number of devices that can be manufactured on a wafer increases thereby reducing the cost of manufacture. However, increasing power density cannot be at the expense of device breakdown voltage and/or removing heat effectively away from the transistor.